Bottom line is that unless you're running a boat load of intense disk intensive operations (which is doubtful for most user applications, especially if you had a sizable memory footprint), you won't see any difference. My friend's got a 200 GB IDE drive on his VAIO that he uses when he's editing digital video - the whole thing is lightning fast. Normal trading apps don't usually generate a ton of disk intensity - unless you don't have enough memory for them and you force high levels of paging that is. If you need or want redundancy/fault tolerance in your disk subsystem - load dual drives and use W2K's mirroring feature. Again, unless for some unique reason you've got a huge disk utilization demand you don't even need separate RAID hardware.